Abstract 13267: Bone Marrow Stem Cell Survival is Prolonged by Up-regulation of miR-21 With Tadalafil Preconditioning Under Oxidative Stress in vitro and Improve Myocardial Remodeling in Ischemic Heart
Background: Aim of this study was to determine if bone marrow-derived mesenchymal stem cell (MSC) survival could be extended when microRNA-21 (miR-21) expression was up-regulated with the treatment of tadalafil (PDE5A inhibitor) on the tumor necrosis factor (TNF-α) family member Fas gene signaling through the PKG-MAPK pathway in vitro and study the grafted cell survival into myocardial remodeling of infarcted rats in vivo.
Methods and Results: Rat MSCs were treated with tadalafil (TadaMSCs, 1μM, 1h) or DMSO as control (ContMSCs) and then, exposed to an oxidative stress with H2O2 (100μM, 4h). Either PKG (DT-3, 1μM, or KT5823, 1μM), MAPK (PD98059, 40μM, or U0126, 25μM) or nitric oxide synthetase (L-NAME, 6mM) inhibitors or miR-21 inhibitor with luciferase construction +/- Fas was administered to MSCs for 1h in advance of tadalafil. The cytoprotective effect of tadalafil, Fas, cell signaling and miR-21 expression assay were analyzed in all MSC groups. Coronary LAD ligation of rats was performed and transplanted with TadaMSCs or ContMSCs. Heart function and histopathology were assessed. In vitro, tadalafil increased miR-21 expression and had favorable cell survival (increased cell counting Kit-8) and anti-apoptotic effects (reduced TUNEL-positive cells). miR-21 overexpression in TadaMSCs and associated cytoprotective effects were significantly reduced after PKG or MAPK inhibition. cGMP activity, p-VASP, p-ERK, STAT3-, Akt-, and Bcl-xl- expression were increased in TadaMSCs. Furthermore, Fas protein expression was reduced in TadaMSCs and was restored by either PKG or MAPK inhibition or by miR-21 inhibition. Luciferase reporter assay verified that miR-21 downregulated Fas protein by targeting 3’-UTR region of Fas mRNA in TadaMSCs. In vivo, reduced TUNEL-positive, increased neoangiomyogenesis, attenuation of remodeling and preservation of ejection fraction in TadaMSC engrafted animal hearts compared with controls.
Conclusion: Tadalafil orchestrates an MSC strategy of cytoprotection during oxidative stress via up-regulation of miR-21 by targeting Fas ligand through the PKG-MAPK signaling pathway. Preconditioning of donor stem cells with tadalafil improved the grafted cell survival in ischemic myocardium and improved heart function.
- © 2013 by American Heart Association, Inc.